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DEPARTMENT OF COMMERCE AND LABOR 

BUREAU OF FISHERIES 

GEORGE M, BOWERS, Commissioner 



CONDITION AND EXTENT OF THE 

NATURAL OYSTER BEDS 

OF DELAWARE 



Bureau of Fisheries Document No. 745 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1911 



DEPARTMENT OF COMMERCE AND LABOR 

/f,3 j BUREAU OF FISHERIES 
It 

GEORGE M. BOWERS, Commissioner 



CONDITION AND EXTENT OF THE 
NATURAL OYSTER BEDS ^ 
OF DELAWARE fJZ 



Bureau of Fisheries Document No. 745 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 
1911 



At 



&$> 



CONDITION AND EXTENT OF THE NATURAL OYSTER 
BEDS OF DELAWARE 

By H. F. Moore 

Assistant, U. S. Bureau of Fisheries 



Bureau of Fisheries Document No. 745 



CONTENTS. 

Page. 

Introduction 3 

Methods of the survey 4 

Description of oyster grounds 7 

Bombay bed 7 

Thrum-cap bed 8 

Over-the-Bar bed 9 

Patches between Over-the-Bar and Sand beds 10 

Sand bed 11 

Leipsic Rock 11 

Bed north of Silver bed 12 

Between Silver bed and Simons Creek 12 

Silver bed 13 

Lumps between Silver and Ridge beds 14 

Drum bed 15 

Ridge bed 16 

Small beds northeast of Ridge bed 18 

Old bed 19 

Outside of Old bed 19 

Scattered patches between Ridge and Southwest beds 20 

Southwest bed 20 

Stone bed 22 

East Line bed , 22 

Flogger bed 23 

The beds in summary 23 

Physical and biological conditions 27 

Tides and currents 27 

Salinity of the water 27 

Enemies of the oyster 28 

2 



CONDITION AND EXTENT OF THE NATURAL OYSTER 
BEDS OF DELAWARE. 



By H. F. Moore, 
Assistant, United States Bureau of Fisheries. 



INTRODUCTION. 

At the solicitation of the Delaware Oyster Survey Commission the 
Bureau of Fisheries during the summer of 1910 undertook a survey 
of the natural oyster beds of Delaware Bay within the jurisdiction of 
the State of Delaware. The State, which was making a survey of the 
planted beds under the supervision of Mr. C. C. Yates, of the United 
States Coast and Geodetic Survey, furnished the triangulation and 
made a small appropriation for the payment of two temporary em- 
ployees during part of the work, but the Bureau of Fisheries fur- 
nished all other personnel, in addition to launches, boats, and 
equipment. 

The steamer Fish Hawk was detailed for the work from June 1 to 
July 10, though, owing to unexpected delays in securing a launch 
able enough for the execution of hydrography in the open waters of 
the bay, she did not actually reach the field of operations until June 
18. Part of the civilian personnel was ordered to the ship on May 26, 
in order to have the equipment in readiness for the anticipated com- 
mencement of work on June 1, on which date the entire party was 
assembled. 

The purpose of the survey was the accurate location and charting 
of the natural oyster beds and the investigation of their present 
condition and productiveness. No previous survey or investigation 
of the beds of this region has been made, and although their approxi- 
mate location is known to the local oystermen with reference to cer- 
tain more or less indefinable natural landmarks, it is difficult for them 
to indicate, even roughly, their general position on the charts. Con- 
cerning some of the beds, and especially the southern extension of 
Flogger bed, the information obtained from the various sources was 
extremely contradictory. 

3 



4 NATURAL OYSTER BEDS OF DELAWARE. 

METHODS OF THE SURVEY. 

The methods employed were those pursued in former surveys of 
like character, and are explained in detail in a description of the beds 
of the James River/ from which some of the following is repeated : 

A "boat sheet" was prepared, on which were accurately platted 
the positions, as determined by triangulation, of lighthouses and the 
towers erected as shore signals. These data were furnished by the 
State and were based on a development of the triangulation employed 
in the survey of the planted or leased beds. 

The oyster beds were discovered by soundings with a lead line, 
but principally by means of a length of chain dragged over the bot- 
tom at the end of a copper wire running from the sounding boat. 
The wire was wound on a reel and its unwound length was adjusted 
to the depth of water and the speed of the launch, so that the 
chain was always on the bottom. Whenever the chain touched a 
shell or an oyster the shock or vibration was transmitted up the wire 
to the hand of a man whose sole duty it was to give heed to such 
signals and report them to the recorder. 

The launches from which the soundings were made were run 
at a speed of between 3 and 4 miles per hour, usually on ranges 
ashore to insure the rectitude of the lines. At intervals of three 
minutes — in some cases two minutes — the position of the boat was 
determined by two simultaneous sextant observations of the angles 
between a set of three signals, the middle one of which was common 
to the two angles, the position being immediately platted on the 
boat sheet. At regular intervals of twenty seconds, as measured 
by a clock under the observation of the recorder, the leadsman made a 
sounding and reported to the recorder the depth of water and the 
character of the bottom, immediately after which the man at the wire 
reported the character of the chain indications since the last sound- 
ing — that is, whether they showed barren bottom or dense, scat- 
tering, or very scattering growths of oysters. 

With the boat running at 3 miles per hour the soundings were 
between 80 and 90 feet apart, and, as the speed of the boat was 
uniform, the location of each was determinable witlrin a yard or two 
by dividing the platted distance between the positions determined 
by the sextant by the number of soundings. The chain, of course, 
gave a continuous indication of the character of the bottom, but the 
record was made at the regular twenty-second intervals observed 
in sounding. 

The chain, while indicating the absence or the relative abundance 
of objects on the bottom, gives no information as to whether they 
are shells or oysters, nor, if the latter, their size and condition. To 
obtain these data it was necessary to supplement the observations 

i Moore, H. F. : Condition and extent of the oyster beds of James River, Virginia. Bureau of Fisheries 
Document No. 729. 



NATURAL OYSTER BEDS OF DELAWARE. 5 

already described by others more definite in respect to the desired 
particulars. Whenever, in the opinion of the officer in charge of the 
sounding boat, such information was required, a numbered buoy 
was dropped, the time and number being entered in the sounding 
book. Another launch, following the sounding boat, anchored 
alongside the buoy, and a quantity of the oysters and shells were 
tonged up, separated by sizes, and counted. 

This boat at each station made a known number of "grabs" 
with the oyster tongs, exercising care to clean the bottom of oysters 
as thoroughly as possible at each grab. In a given depth of water 
and using the same boat and tongs, an oysterman will cover prac- 
tically the same area of the bottom at each grab, but, other factors 
remaining the same, the area of the grab will decrease with an increase 
in the depth. 

Careful measurements were made and tabulated showing the 
area per grab covered by the tonger employed on the work at each 
foot of depth of water and for each pair of tongs and boat used. 
With these data, and knowing the number of "grabs," the number 
of oysters of each size per square yard of bottom was readily obtain- 
able by simple calculation. The following example will illustrate 
the data obtained and the form of the record : 



Department op Commerce and Labor, 
bureau of fisheries. 

field record of examinations op oyster beds. 

General locality, Delaware Bay, Delaware. 

Local name of oyster ground, Over-the-Bar. 

Date, July 9, 1910. Time, 8.50 a. m. 

Angle, B 146-B 147. Buoy No. 6. 

Depth, 18 feet. Bottom, soft. 

Condition of water, clear. 

Density, 1.008. Temperature, 25° C. 

Current, Stage of tide, one hour flood. 

Tongman, M. A. Duffield. 

No grabs made, 8. Tongs, 20 feet. 

Total area covered, 2.5 sq. yds. 

AT . . , (1 in., 13. 1 in-3 in., 129. 

No oysters taken ^ ^ ^ 59 4 {n ; n 

Quantity shells, 14. 

I Spat per square yard, 5.2. 
Culls per square yard, 51.6. 
Counts per square yard, 28.0. 



This furnishes an exact statement of the condition of the bed at a 
spot which can be platted on the chart with error in position of not 
more than a few yards. From the data obtained a close estimate may 
be formed of the number of bushels of oysters and shells per acre in 
the vicinity of the examination and, by multiplying the observations, 
for the bed as a whole. In the course of the survey 590 observations 
were made at various places, principally on the natural rocks, but 
some on the barren bottoms also. 



6 NATURAL OYSTER BEDS OF DELAWARE. 

In estimating the relative productiveness of the bottoms it appeared 
advisable to depart from the methods employed in the James River 
survey on account of the difference in the conditions under which the 
industry is prosecuted. Where tongs are used exclusively, a bed 
with a given quantity of oysters lying in shoal water is more valuable, 
commercially, than one with the same quantity of oysters in deep 
water, owing to the fact that the labor of the tohger is more efficient 
on the former. As has been pointed out, the area covered by a 
"grab" decreases with the depth, other factors being the same, and 
moreover the deeper the water the greater is the labor involved in 
making the grab and the smaller is the number of grabs which can be 
made in a given time. 

In Delaware Bay, while there is a certain amount of tonging during 
the fall and at such times as the weather will permit in winter and 
early spring, the most important and productive fishing is by means 
of dredges, the use of which is permitted from April 15 to June 30, 
inclusive. In dredging, the effects of varying depths of water, within 
reasonable limits, are practically negligible so far as the catch is con- 
cerned. The time required for winding in from deep water is greater 
than from shallow water, but as the dredge is approximately equally 
efficient whatever the depth, and as the difference in the time required 
in winding is small as compared with the period during which the 
dredge is on the bottom, the factor of depth, so important in tonging, 
is practically inconsiderable. 

The classification adopted in this report is as follows : 

Depleted bottom Less than 25 bushels per acre. 

Very scattering growth Between 25 and 75 bushels per acre. 

Scattering growth Between 75 and 150 bushels per acre. 

Dense growth Over 150 bushels per acre. 

As the region is important for the production of seed rather than 
market oysters, all sizes are included in the estimates of the density 
of oyster growth, but all loose shells and other debris commonly 
dredged are excluded. "Depleted bottom" is not necessarily that 
which was formerly productive but now practically barren, but is 
merely an expression of the present impoverishment of the bed without 
respect to its past. In some cases it may be a formerly barren area 
slowly coming into productiveness. 

The bottom rated as bearing a "very scattering growth" is the 
least productive bottom capable of furnishing a livelihood to the 
dredgers. 

In the course of the survey 16,435 acres, or over 25 square miles, 
were explored with sounding lines and chains. Of this area 2,144 
acres were found to be included in oyster beds of varying degrees of 
productiveness. In the survey the chain was dragged over 124 miles 
of the bottom, soundings were made at 5,772 places, and the position 
of the boat was instrumentally determined at 819 points. 



NATURAL OYSTER BEDS OF DELAWARE. 



DESCRIPTION OF OYSTER GROUNDS. 



BOMBAY BED. 

This is the northernmost public oyster bed within the confines of 
Delaware. Its northern limit is opposite the upper pier at Woodland 
Beach, and its southern end is a little below the small creek known 
locally as Tombstone. Its inner or southwestern edge is from 200 to 
400 yards from shore, the average width of the bed is about one- 
fourth mile, and the total length slightly in excess of 1 mile. 

The estimated area, density of growth, and contents of the bed 
are as follows: 

Oyster Growth on Bombay Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 
oysters. 




Acres. 

Ill 

12 

6 

26 


Bushels. 

250 

103 

22 




Bushels. 

115 

23 

5 




Bushels. 
365 
126 

27 



Bushels. 
40, 515 


Scattering. . .'. 


2,512 




162 











Total 


155 








43,189 











The dense area comprises a broad strip running along the entire 
inshore edge of the bed. The scattering areas are two, the larger 
lying near the middle of the outer edge of the bed and the smaller, a 
very narrow strip, on the offshore edge of the lower end. Both 
merge more or less gradually into the dense area with which they are 
continuous. The area of very scattering growth is a small patch 
situated near the offshore part of the upper end of the bed, in the 
midst of the depleted bottom. The latter appears to be a formerly 
moderately productive area which has become covered by a deposit 
of mud and now produces no oysters, although there are numerous 
buried shells lying on a hard bottom about 6 inches beneath the 
present surface. This bed differs from all others of the region treated 
in this report in being founded on a stony bottom, a considerable 
proportion of the oysters taken being attached to rock fragments. 
The oysters are in small clusters, with thin, sharp shells. Small 
oysters predominate, not only numerically but by measure. No 
drills were found and, reasoning from the low salinity of the water, 
probably do not occur. The specific gravity of the water at the time 
of examination, July 10, 1910, was about 1.005, and it is likely that 
the bed suffers periodically during freshets. The average depth of 
water is about 8 to 10 feet. 

It was reported that there were oysters between the piers, but none 
were found, although there were a few attached to the piling and 
lying on the bottom in its vicinity. 
68309°— 11 2 



8 



NATURAL OYSTER BEDS OF DELAWARE. 



The details of the examination of this bed are shown in the following 
table : 

Details of Examinations of Bombay Bed. 



Station 
num- 


Date of 
exami- 
nation. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


183 


1910. 
July 10. . 
...do 


Feet. 
10 
10 
10 

11 

10 
12 
12 
11 
12 
12 
10 
11 
10 
10 
11 


Dense 


No. 
1.6 
10.5 
11.0 
15.8 
28.4 
9.5 
52.0 
74.2 
11.0 
35.2 
0.0 
0.0 
0.0 
0.0 
0.0 


No. 
35.2 
42.0 
65.8 
34.2 
54.2 
17.9 
58.4 
57.4 
12.6 
0.0 
6.3 
0.0 
0.0 
0.0 
0.0 


No. 
2.6 
12.6 
19.5 
3.2 
20.5 
9.5 
13.7 
10.0 
3.7 
1.0 
0.5 
0.0 
0.0 
0.0 
0.0 


Bu. 

129 

184 

269 

175 

299 

96 

387 

461 

83 

123 

22 










Bu. 

26 

126 

195 

32 

205 

95 

137 

100 

37 

10 

5 










Bu. 
155 


184 


do 


310 


189 


...do 

...do 

...do 

...do 

...do 


do 


464 


191 

192 

195 


do 

do 

do 


207 
504 
191 


197 


do 

...do 


524 


199 


...do 


561 


194 


...do 

...do 

...do 

...do 

...do 




120 


198 


do 


133 


186 




27 


185 







187 


do 





188 


...do 


...do... 





190 


...do 


do 














THRUM-CAP BED. 

For a distance of about 5 miles below Bombay bed the bottom is 
reported to be barren, with the possible exception of a few patches of 
insignificant size, and it was not deemed warrantable to incur the 
expense of an examination. 

Thrum-cap bed is a somewhat triangular area lying about 1 mile 
offshore opposite the small stream known to the oystermen as Hay 
Ditch. It covers an area of about 78 acres, of which it is estimated 6 
are covered by a dense growth, 14 by scattering, and 55 by very scat- 
tering, and 3 acres are characterized by a'total absence of oysters, but 
with scattered shells buried in the mud. 

The areas of dense and scattering growth form a narrow strip on 
the inshore edge of the bed, with the denser area at the upper end. 
The bottom covered with very scattering growth stretches in gradually 
decreasing productiveness from the outer edge of this strip toward 
the deeper water. The depleted area is a small patch where the dense 
growth shades off into the surrounding barren bottom. The depth of 
water on the bed varies from about 18 feet at the inshore edge to 22 
feet on the outer border. 

It is estimated that the bed contained at the time of examination 
4,195 bushels of oysters of all sizes, of which the dense area bore 1,164 
bushels, the scattering 1,106 bushels, and the very scattering 1,925 
bushels. 

There were comparatively few dead oysters, and no indications of 
the presence of drills were observed. In July the specific gravity of 
the water varied from about 1 .003 at low water to 1 .01 1 at high tide. 



NATURAL OYSTER BEDS OF DELAWARE. 9 

The results of the examinations of this bed are shown in the follow- 
ing table: 

Details of Examinations of Thrum-cap Bed. 



Station 
num- 
ber. 



179. 
181. 

178. 
180. 



Date of 
exami- 
nation. 



1910. 
July 9 

...do 

...do 

..do .... 



Depth 

of 
water. 



Feet. 
19 
20 
22 
19 



Character of growth. 



Dense 

Scattering 

Very scattering 
Depleted 



Oysters caught per 
square yard. 



Spat. Culls. Counts 



No. 
4.4 
5.5 
1.7 
0.0 



No. 
28.4 
12.2 
3.3 
0.0 



No. 
8.0 
1.7 
1.7 
0.0 



Estimated quantity 
oysters per acre. 



Seed. Market. Total 



Bu. 
114 
62 

18 




Bu. 



Bu. 



194 
79 

■■',5 




OVER-THE-BAR BED. 

This bed, like the preceding, from which it is separated by a dis- 
tance of a little over one-eighth of a mile, lies just beyond the edge of 
the shifting sands, which extend to about the 12-foot curve. It is 
about 1 J miles from shore, and takes its name from its position some 
distance outside of a long sand bar, which, according to the naviga- 
tional charts, is covered by about 4 feet of water at low tide, but on 
which the present survey found water a little deeper. The depth on 
the bed itself varies from 15 to 20 feet. 

The extent and general condition of the bed in July, 1910, is shown 
in the following table : 

Oyster Growth on Over-the-Bar Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 
oysters. 




Acres. 

109 

15 

39 


Bushels. 

103 

41 




Bushels. 

162 






Bushels. 

275 

41 




Bushels. 
29,975 
615 


Very scattering 


Depleted 









Total 


163 








30,590 











The dense growth is found on two areas, 41 and 68 acres in extent, 
respectively, separated by a depleted area containing nothing but 
buried shells. The upper area is long and narrow and contains a 
large preponderance of oysters over 3 inches long. The northern 
end of the lower area is similar, with four or five times as many 
large oysters as small ones, but in the southern the two are in 
approximately equal quantity, and the average of both sizes is about 
335 bushels per acre. The area of very scattering growth is found at 
the inshore edge of the southern part of the bed, and was apparently 
formed by a recent strike on a previously depleted area. The three 
depleted areas He at the ends and the middle of the bed, the latter in 
reality separating the rock into two distinct parts. The depleted 



10 



NATURAL OYSTER BEDS OF DELAWARE. 



bottom bears no oysters and but few exposed shells and, apparently, 
has been formed either by the silting of sparsely productive bottom 
or by shells dragged by dredging from the rock on to the adjacent 
muddy bottom. 

The oysters throughout the entire bed are long, narrow, sharp-edged, 
and inferior in quality, and are almost invariably in clusters, whose 
bases are buried in soft mud. The bottom throughout is soft, and 
there is apparent nowhere any depth of shell deposits such as are 
found on Silver bed and the Ridge. 

The details of the examinations made on this bed are shown in the 
following table : 

Details op Examinations of Over-the-Bar Bed. 



Station 


Date of 
exami- 
nation. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 




1910. 
July 9 
...do... 


Feet. 
18 
18 
18 
20 
19 
21 
17 
18 
20 
20 
21 




No. 
15.2 
12.0 
5.2 
9.2 
0.8 
5.6 
0.8 
0.0 
0.0 
0.0 
0.0 


No. 

28.8 

28.0 

51.6 

5.6 

9.2 

6.1 

10.8 

0.0 

0.0 

0.0 

0.0 


No. 

14.8 
8.4 
28.0 
10.4 
15.6 
26.1 
0.0 
0.0 
0.0 
0.0 
0.0 


Bu. 

154 

140 

198 

52 

35 

41 

41 










Bu. 

148 

84 

280 

104 

156 

261 












Bu. 

302 


170. 


do 

do 


224 


171 


do... 


478 


172 


.do... 


do 


156 


174 


.do... 


do 


191 


177 


...do... 


do 


302 


167 


.do... 




41 


168 


do... 







173 


.do... 


do 





176 


.do . . . 


do 





182 


do ... 


do 





1 







PATCHES BETWEEN OVER-THE-BAR AND SAND BEDS. 

In the area between these beds are several small scattered patches 
of oysters, but two of which were examined to determine their char- 
acter. One of these has an area of about 16 acres and is estimated 
to contain about 1,000 or 1,200 bushels of oysters. The other is 
about 5 acres in extent and contains probably about 200 bushels of 
oysters. On both beds and probably on other small - patches in the 
vicinity the oysters are long, thin, and narrow, and are found in 
scattered clusters. 

The following table exhibits the data obtained from the examina- 
tions : 

Details of Examinations of Patches between Over-the-Bar Bed and Sand 

Beds. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


160. . 


1910. 
July 8 
.do 


Feet. 
19 
15 




No. 




No. 

2.8 
3.0 


No. 
3.2 
6.3 


Bu. 
10 
11 


Bu. 
32 
63 


Bu. 
42 


162. . 


do 


74 











NATURAL OYSTER BEDS OF DELAWARE. 



11 



SAND BED. 

Sand bed lies nearly north of the Ridge and northeast of Silver bed, 
being separated from the latter by a distance of about one-third of a 
mile. It covers an area of about 54 acres, of which 16 acres are cov- 
ered by a dense growth of oysters and 11 acres by a scattering 
growth, the remaining 27 acres being depleted. 

The productive bottom forms a zone along the inner edge of the 
bed, the southern and middle portions bearing the denser growth. 
The depleted bottom occupies the outer half of the bed. It is esti- 
mated that the bed contained about 4,600 bushels of oysters of all 
sizes at the time of examination, and that of these 3,700 bushels were 
on the area of dense growth, 700 bushels on the very scattered growth, 
and 200 bushels on the depleted bottom. Oysters over 3 inches long 
preponderated on the productive portions of the bed, but were inferior 
in quantity on the depleted area. 

The oysters are superior in shape to those found on the bars north 
of this, being in smaller clusters and rounder. Dead oysters were 
comparatively few, and no indications of the drill were noted. 

Several boats were observed working on Sand bed during the latter 
part of June, and it is reported that the bed was dredged to some 
extent earlier in the season. 

The following examinations were made: 

Details of Examinations of Sand Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated 
oysters per 


juantity 
acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. Total. 


154 


1910. 
July 8 
. ..do 


Feet. 
20 
19 
18 
19 
19 




No. 
1.2 
4.0 
0.0 
0.4 
1.6 


No. 

24.4 
1.2 
0.0 
2.4 


No. 
14.4 

4.8 
0.0 
0.4 
0.4 


Bu. 

90 
18 


10 

6 


Bu. 
144 

48 

4 
4 


Bu. 


159 






155 


...do 






156 


...do 


do 




157 


...do 


do 


10 









LEIPSIC ROCK. 

This is a small but exceedingly prolific bed lying in the mouth of 
Leipsic Creek within one-eighth of a mile of the shore. It is approxi- 
mately circular in outline and consists of about 4 acres of very dense 
growth. It is estimated that the bed bears nearly 3,000 bushels of 
oysters, practically none of which is over 3 inches in length, and it 
is probable that it represents a recent rejuvenescence of an old bed. 
There is a deep deposit of shells forming the core of the bed, but 
around the edges this is covered by a deposit of mud which appears 
to be encroaching on and causing a gradual contraction of the pro- 
ductive area. It is probable that the oysters are subject to peri- 
odical destruction from fresh water and mud carried by freshets. 



12 



NATURAL OYSTER BEDS OF DELAWARE. 



So far as could be learned the rock has not been worked for several, 
years. 

The following examinations were made : 

Details of Examinations of Leipsic Rock. 



Station 
number. 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


140 


1910. 
July 7 
...do.... 
.do 


Feet. 

11 
12 
10 




No. ■ 

41.0 

0.0 

118.0 


No. 

114.5 

14.8 

300.0 


No. 
1.4 
0.4 
1.6 


Bu. 

544 

52 

1,400 


Bu. 
14 
4 
16 


Bu. 

558 


144 

14, r ). . . 


do 

do 


56 

1,476 











BED NORTH OF SILVER BED. 

North of the western end of Silver bed and separated from it by 
about one-eighth of a mile of soft bottom in which scattering shells 
are buried is a nameless bed covering about 25 acres. There are 
about 8 acres covered by scattering growth estimated to contain 
about 900 bushels of oysters and about 17 acres of very scattering 
oysters containing about 750 bushels. The northern part of the 
bed, which bears the heaviest growth, has a substratum of shells, 
but the southern edge lies on sandy bottom. The proportion of 
large oysters is greater than on Silver bed. 

The following observations were made : 

Details of Examinations of Bed North of Silver Bed. 



Station 
number. 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre . 


Spat. 


Culls. 


Counts. 


Seed 


Market. 


Total. 


158 


1910. 
July 8 
...do 


Feet. 
14 
13 




No. 
4.5 
4.0 


No. 

6.7 
2.2 


No. 
7.8 
2.2 


Bu. 

- 39 

22 


Bu. 
78 
22 


Bu. 
117 


152 




44 











BETWEEN SILVER BED AND SIMONS CREEK. 

Almost continuous with Silver bed and stretching for a distance of 
nearly one-half of a mile toward the mouth of Simons Creek is a bed of 
about 17 acres lying on the mud and sand. Its most productive 
area is nearest Silver bed, and the opposite end is bare except of scat- 
tered shells. The best part, about 5 acres in extent, bears a scatter- 
ing growth of oysters estimated to contain about 375 bushels, and 
the area of very scattering growth which adjoins it bears about the 
same quantity on its 7 acres. The depleted bottom is practically 
bare at present, but is in a condition to catch a small set under 
favorable conditions. 



NATURAL OYSTER BEDS OF DELAWARE. 



13 



The following table shows the results of examinations : 
Details op Examinations op Bed between Silver Bed and Simons Ckeek. 



Station 
number. 



166... . 

165 

111.... 



Date of 
exami- 
nation. 



1910. 
July 8 
...do.... 
June 29 



Depth 

of 
water. 



Feet. 
9 
9 
14 



Character of growth. 



Scattering 

Very scattering 
Depleted 



Oysters caught per 
square yard. 



Spat. Culls. Counts. 



No. 
2.9 
0.0 
0.0 



No. 
3.4 
4.3 
0.0 



No. 
5.4 
3.7 
0.0 



Estimated quantity 
oysters per acre. 



Seed. Market. Total. 



Bu. 
22 
15 





Bu. 



Bu. 



SILVER BED. 

This bed, which is said to derive its name from the silvery color of 
the shells found on the hard rock, is, excepting the Ridge, the largest 
and most important natural bed in Delaware. It lies about 1 mile 
east of the mouth of Dona River, locally known as Simons Creek. 
The bed has a maximum extent of about a mile east and west and 
slightly over a half mile north and south, and it lies in a depth of 
water varying from 8 to 12 feet. 

The following table shows its general extent and condition in 

July, 1910: 

Oyster Growth on Silver Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 
3 inches. 


Over 
3 inches. 


Total. 


content of 
oysters. 




Acres. 
65 
20 
45 
140 


Bushels. 

171 

82 

25 

8 


Bushels. 
74 
27 
21 
2 


Bushels. 

245 

109 

46 

10 


Bushels. 
15,925 




2,180 




2,070 




1,400 






Total 


270 








21,575 













The most productive parts of the bed lie in its northeast half and 
include a belt of dense and scattering growth about one-half mile 
long and varying from one-eighth to one-third mile in width. 

A considerable part of the bottom covered by the bed is macadam- 
ized with a dense accumulation of shells, or probably two such areas 
separated by a belt of muddy bottom. In places the bottom was so 
hard with compacted shells and so smooth that a boat anchor would 
not take hold. Although this bed is not now raised above the sur- 
rounding barren bottom, it is probable that it originally formed a 
knoll, the crest of which has been cut away by dredging and tonging. 

The area of dense growth lies in a compact body occupying the 
middle of the eastern half of the bed, gradually merging with two 



14 



NATURAL OYSTER BEDS OF DELAWARE. 



small areas of scattering growth at the northwest and southeast ends, 
respectively. There is a third area of scattering growth near the 
western end of the bed. The very scattering growth forms a zone 
around the western and part of the southern side of the more prolific 
bottom, lying on a substratum of compacted shells. Most of the 
western half of the bed is composed of depleted bottom, which also 
extends as a narrow strip around practically the entire circumfer- 
ence of the rest of the bed, the bottom being generally hard and 
shelly with occasional patches of mud. 

In general the present condition of the bed indicates a former 
greater extent of productive bottom. There is every indication that 
it has been closely dredged during the past season, and the present 
content of oysters is probably but a small proportion of the quantity 
on the bottom at the beginning of the season. The shells are in 
excellent condition to receive a set of spat, and under favorable cir- 
cumstances the bed should speedily recuperate. There were com- 
paratively few dead oysters, and drills or borers do not appear to be 
troublesome. 

The following observations were made: 

Details op Examinations of Silver Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 
of 

water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


58 


1910. 
June 25 
June 29 
July 8 
...do 


Feet. 
14 
14 
13 
10 
14 
14 
9 
13 
11 
13 

13 
13 
11 
11 
14 
13 




No. 

23.7 
5.9 
1.5 
8.7 

12.2 
1.4 
4.3 
0.4 
2.4 
2.6 


No. 

65.0 

21.1 

29.6 

40.0 

7.4 

22.2 

22.9 

3.3 

7.9 

4.5 


No. 

12.2 
6.7 
7.8 
2.9 
1.9 
3.3 
2.9 
1.2 
1.7 
3.3 


Bu. 

310 

94 

109 

170 

69 

83 

95 

13 

36 

25 


Bu. 
122 
67 
78 
29 
19 
33 
29 
12 
17 
33 


Bu. 

432 


110... 


do 


161 


149 . 


...do 


187 


163... 


do 


199 


55... 


June 25 
July 8 
...do 




88 


147 




116 


164 


do 


124 


59... 


June 25 
June 27 
July 8 
June 25 
...do 




25 


100 


do 


53 


150 


do 


58 


52... 






53... 




0.3 
0.0 
0.0 

1.4 
0.0 

1.1 


4.5 
0.0 
2.8 
1.0 
0.0 
2.2 


0.0 
0.0 
0.3 
0.7 
0.0 
0.0 


, 17 


10 
8 


11 




3 
7 




17 


60 


...do 


do 





98 


June 27 
...do 


do 


13 


99 


do 


15 


109 


June 29 
July 8 


...do 





148... 


...do 


11 









LUMPS BETWEEN SILVER AND RIDGE BEDS. 



Lying between Sand and Silver beds on the north and Ridge and 
Drum beds on the south are a number of small lumps and patches 
surrounded by a considerable area of barren bottom. Eight of these 
areas were located by the survey, most of them covering areas of 3 
or 4 acres, and there are probably a number of others, as on account of 
their small size and irregular distribution but little time was spent in 



NATURAL OYSTER BEDS OF DELAWARE. 



15 



looking for them. But three of these places were examined in detail, 
and their location may be determined by an inspection of the chart. 
One of them was about 3 acres in extent and was estimated to con- 
tain about 2,500 bushels of long, sharp-edged oysters in large clus- 
ters, growing on a soft, muddy bottom. The other two spots exam- 
ined bore a very scattering growth. The largest of these, about one- 
fourth mile inshore of the upper end of Drum bed, was estimated 
to be about 8 acres in extent and to contain about 300 bushels of 
oysters. The other, just south of the middle of Silver bed, has an 
area of about 4 acres and contained at the time of examination about 
120 bushels of oysters. 

The five areas located but not examined varied in extent from 
about 1 to 14 acres, and are situated variously. They are shown on 
the chart as unshaded places surrounded by red lines. Judging 
from the chain readings none of them is particularly productive. 

The following observations were made in this region: 

Details op Examinations op Lumps between Silver and Ridge Beds. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


96 


1910. 
June 27 
...do 


Feet. 
18 
15 
13 




No. 
1.4 
0.7 
0.0 


No. 

28.0 
4.1 
2.2 


No. 

75.2 
1.9 
2. 2 


Bu. 

103 

17 

8 


Bu. 
752 
19 

22 


Bu. 
855 


86 




36 


97 


...do 


do 


30 











DRUM BED. 

Drum bed lies west of and very close to the depleted edge of the 
ridge and about 1 mile from shore. It has a length of over one-half 
mile, a width of about one-fourth mile, and a total area of approxi- 
mately 68 acres. Its condition and the relative extent of oyster 
growths of the several degrees of productiveness are shown in the 
following table: 

Oyster Growth on Drum Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 
oysters. 


Dense 


Acres. 
16 
21 
19 
12 


Bushels. 

139 

30 

32 

1 


Bushels. 

83 

65 

18 

6 


Bushels. 

222 

95 

50 

7 


Bushels. 
.3,552 




1,995 




950 




84 






Total 


68 








6,581 











16 



NATURAL OYSTER BEDS OF DELAWARE. 



The most prolific part of the bed is an area about one-fourth mile 
square extending across its middle, consisting of an area of dense 
growth flanked on each side by one bearing a scattering growth. The 
northern end of the bed is composed of a gradually narrowing area 
of very scattering growth, and there is a small patch of similar char- 
acter at the inside corner of the southern end. 

The depleted bottom is in two patches, one adjoining the scattering 
and very scattering growths at the lower end and the other interposed 
between the dense scattering and very scattering oyster deposits just 
above the middle. The bottom is soft on the areas of very scattering 
growth and on part of the northernmost depleted area, but is elsewhere 
hard and shelly. 

Small oysters exceed in quantity those over 3 inches long, excepting 
on the area of scattering growth, where there are about twice as many 
large as small ones. Loose shells are in fair abundance and of a char- 
acter to catch a good set under favorable conditions. 

The following observations were made : 

Details of Examinations of Drum Bed. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


47 


1910. 

June 25 

.do.. 


Fed. 
16 
16J 
17 
17 
17 
18 
18 
17 
15 
17 




No. 
27.2 

ie! o 

4.0 
7.2 
1.4 
1.6 
1.6 
0.0 
0.0 
0.0 


No. 

18.8 

30.0 

23.2 

13.2 

10.0 

2.8 

9.2 

7.6 

0.4 

0.0 


No. 
3.6 
7.6 

13. 6 
3.2 
8.2 
8.2 
1.6 
2.0 
0.4 
0.8 


Bu. 

161 

161 

95 

71 

4 

15 

37 

27 

1 




Bu. 

36 

76 

136 

32 

82 

82 

16 

20 

4 

8 


Bu. 
197 


do 


237 


107 ... 
51 

84 .... 
106 


June 29 
June 25 
June 27 
June 29 
do 


do 


231 




103 


do 


86 


do 


97 




53 


108 


do 


do 


47 


85 


June 27 
do 




5 




8 











RIDGE BED. 

i 

The Ridge bed, known to the oystermen as "The Ridge," is at 
present the most important natural bed in Delaware, and during the 
period of the present survey it sustained by far the heaviest dredging. 
During the latter half of June numerous vessels were at work daily 
and until the end of the month, when the dredging season closed, there 
appeared to be a fair catch. 

The Ridge lies about H miles from the nearest shore, midway 
between Dona River and Mahon River. It is triangular in shape, 
with a deep indentation or slough of muddy bottom projecting deeply 
into its base at the southern end. It has an extent of slightly over 1 
mile north and south and its southern end is almost of equal extent 
east and west. It has a total area of 371 acres and the most produc- 
tive bottom, that which is rated in this report as bearing dense and 



NATURAL OYSTEE BEDS OF DELAWARE. 



17 



scattering growths, stretches from the northern apex to about the 
middle of the bed, where it divides into two limbs astride the slough 
before alluded to. 

It is evident that this bed, like Silver bed, is an old one, and without 
doubt its central portions, those which now bear the heaviest growth 
of oysters, were formerly elevated above the surrounding bottom to 
form a shoal or ridge which has been pulled down and in large part 
carried away by the oystermen, particularly the dredgers, until at 
present the water over it shoals but little as compared with the sur- 
rounding barren areas. The great deposit of shells which originally 
existed has been taken up and the bottom so denuded that in places 
the originally underlying mud has been brought to the surface. Many 
little patches of bare mud were found where there was every reason to 
expect a deposit of shells and oysters and it was apparent that the bed 
was being overworked. 

The general condition and extent of the bed at the end of June, 
1910, is shown in the following table: 

Oyster Growth on Ridge Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 

oysters. 


• 


Acres. 
49 
86 
65 
171 


Bushels. 

160 

96 

30 

4 


Bushels. 

23 

25 

21 

1 


Bushels. 

183 

121 

57 

5 


Bushels. 

8,967 




10,406 




3,705 




855 






Total 


371 








23,933 













The dense areas are two in number, separated by an area of scat- 
tered growth. The smaller of these areas lies at the northern apex 
of the bed and the larger one is a long belt along most of its eastern 
side. More or less soft mud is to be found in the former, especially 
near its upper edge, but the latter rests on a solid substratum of 
shells. 

The lower end of the larger dense area gradually verges into a 
small spot of scattering growth, but most of the bottom bearing 
a growth of this character is embraced in a long, somewhat S-shaped 
strip running from near the northern end of the bed almost to its 
southwest corner. The northern end, especially between and adja- 
cent to the dense growths, is most productive. 

The very scattering growth is all confined to the southern edge of 
the bed, most of it being between the mud slough and the dense and 
scattering growth. Excepting close to the more productive areas 
there is much muddy bottom in this area. Most of the depleted 



18 



NATURAL OYSTER BEDS OF DELAWARE. 



bottom lies on the west side of the bed, but there is a narrow strip 
along the eastern edge and embracing the southern end of the dense 
and scattering growth. Much of the depleted area is in reality 
denuded or barren, and although most of it lies on hard bottom 
there are numerous muddy spots, especially near the southern edge. 

On this bed as a whole and especially on the more productive 
areas small oysters are in great preponderance. In many cases 
there were quantities of oysters so small that they fell between the 
teeth of the tongs. 

The following observations were made on this bed : 

Details of Examinations of Ridge Bed. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 




1910. 
June 26 
June 27 

do.... 


Feet. 
17 
18 
10 
10 
10 
18 
10 
15 
14 
15 
10 
17 
10 
16 
17 
15 
14 
16 
17 
16 
16 
10 
13 
13 




No. 

20.0 

31.2 

29.1 

19.2 

16.0' 

17.2 

28.8 

7.4 

4.8 

2.2 

0.8 

12.4 

0.0 

1.2 

2.0 

0.0 

2.6 

0.0 

0.4 

0.0 

0.0 

0.0 

0.0 

0.0 


No. 

20.0 

21.2 

16.0 

7.6 

12.0 

13.0 

4.4 

10.7 

1.1 

3.7 

10.4 

5.2 

0.0 

2.0 

2.4 

0.0 

0.7 

0.0* 

0.4 

0.0 

0.0 

0.0 

0.0 

0.4 


No. 

3.9 
1.0 
1.0 
2.0 
4.0 
2.8 
2.0 
1.9 
0.7 
5.2 
2.4 
0.0 
0.0 
0.0 
0.0 
0.0 
0.4 
0.0 
0.0 
0.0 
0.0 
0.0 
0.0 

1.1 


Bu. 

140 
183 
158 
94 
98 
108 

no 

63 

21 

21 

39 

02 



11 

15 



12 



3 









1 


Bu. 
39 

10 
10 
20 
40 
28 
20 
19 
7 

52 
24 





4 







11 


Bu. 
179 


91 


do . 


199 


93 


....do 


174 


02 


June 26 
do 




114 


05 


.do 


138 


09 


...do 

June 27 

...do 

June 20 
.do 


.do 


136 


92 


.do 


136 


101 


.do 


82 


01 




28 


63 


"do 

.do 


73 


79 


June 27 
.do .. 


63 


90 


....do .' 


62 


04 


June 20 

...do 

do 







66 




11 


70 


.do 


15 


80 


June 27 
.do .., 


.do. 





81 .. 


....do 


16 


82 


do 


. ...do 





83 . 


do . 


do 


3 


87 


do 


. do 





88 


do 


. .do 





89 


do 


.do 





102 .. 


...do 

...do 


. do 





103 


. do 


12 









SMALL BEDS NORTHEAST OF RIDGE BED. 

Northeast of the Ridge is a small patch of about 7 acres of very 
scattering growth which is estimated to contain about 200 bushels 
of oysters, most of them over 3 inches in length. 

The following results were obtained from an examination of this 
area : 

Details of Examinations of Small Beds Northeast of Ridge Bed. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
" square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


94 


1910. 
June 27 


Feet. 

18 




No. 



No. 
1.4 


No. 
2.4 


Bu. 
5 


Bu. Bu. 
24 29 











NATURAL OYSTER BEDS OF DELAWARE. 



19 



OLD BED. 

Old bed lies close to the southeastern edge of the Ridge, from which 
it is separated by a narrow strip of mud with many buried shells. 
It is stated that the dredgers sometimes haul across the barren 
bottom from one bed to the other. 

The condition and extent of the bed as determined by the survey 
were as follows: 

Oyster Growth on Old Bed. 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 
oysters. 




A cres. 
20 
17 


Bushels. 
40 
10 


Bushels. 
2 
3 


Bushels. 
42 
13 


Bushels. 
840 




221 






Total 


37 








1,061 











Although the bed is at present not very productive it has the 
appearance of former greater value. It lies on a dense bed of shells 
and is undoubtedly the remnant of an old accumulation. There are 
very few. large oysters to be found, but the young growth is fair in 
places and the conditions for a new set are good. The bed evidently 
has been subjected to severe dredging. 

The following observations were made: 

Details of Examinations of Old Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


76 


1910. 
June 27 
June 30 
..do.. 


Feet. 
16 
17 
19 
19 
19 
17 
18 
17 
20 




No. 

10.4 
6.0 
0.8 

10.4 
4.8 
0.0 
1.2 
0.0 
0.6 


No. 
2.8 
1.4 
5.6 

11.6 
4.4 
2.0 
2.0 
1.2 
4.4 


No. 
0.0 
0.0 
0.8 
0.0 
0.0 
0.0 
0.8 
0.4 
0.0 


Bu. 

46 
26 
22 
77 
32 

7 
11 

4 
18 


Bu. 


0" 
8 



8 
4 



Bu. 
46 


130. . 




26 


131 


...do 


30 


132... 


...do.... 


...do 


77 


133 


...do 

June 27 
...do.. 


...do 


32 


71 




7 


75... 


....do 


19 


78 


do . 


.do 


8 


134... 


June 30 


...do 


18 









OUTSIDE OF OLD BED. 

Immediately outside of Old bed is an area of about 16 acres, sur- 
rounded by sand, for which the oystermen appear to have no name, 
if, even, they are aware of its existence. But one observation was 
made at this place, where a dense growth of young oysters was found. 
If the other parts of the bed are equally productive this patch con- 
tains about 6,800 bushels of oysters, practically all of them under 3 
inches in length. The present growth is apparently of recent origin. 



20 NATURAL OYSTER BEDS OF DELAWARE. 

The following results were obtained from the examination : 
Details op Examinations op Beds Outside of Old Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


77 


1910. 
June 27 


ten. 
15 




No. 
35.0 


No. 
&3.4 


No. 
15.0 


Bu. 
414 


Bu. 

15 


Bu. 

429 









SCATTERED PATCHES BETWEEN RIDGE AND SOUTHWEST BEDS. 

On the soft bottom lying between these two beds are a number of 
little patches of oyster growth, of which five were located with the 
chain and three were examined by tonging. The latter were all 
highly productive, and they probably represent the possibilities of 
oyster production in this vicinity on beds not frequented by the 
dredgers. 

The three beds examined covered a total of 11 acres, and it is 
estimated that they contained about 5,300 bushels of oysters, of which 
nearly three-fourths were over 3 inches long. Based on the results 
of the examination, and assuming that the other beds found are equally 
productive, thefiVe beds probably contain about 11,000 bushels, and 
it is probable that at least 20,000 bushels are scattered in little 2 to 5 
acre patches in the vicinity. 

The following table shows the data obtained from examinations: 

Details of Examinations of Small Scattered Patches Between Ridge and 

Southwest Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
' square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


40 


1910. 
June 22 
.do 


Feet. 
12 
14 
14 




No. 
20.3 
15.2 
15.2 


No. 
21.1 
30.4 
14.4 


No. 

21.1 

20.7 
71.5 


Bu. 
145 
159 
104 


Bu. 
211 

207 
715 


Bu. 

356 


42 . 


...do.... 


366 


71... 


June 27 


do 


S19 









SOUTHWEST BED. 

Southwest bed lies in the southeastern part of the present pro- 
ductive natural oyster grounds of the State and its southern edge is 
about one-fourth mile north of the "east line" which separates the 
private beds from the public ones. It has a north and south extent 
of upward of one-half mile and a maximum width of about one-third 
mile, containing all told about 106 acres. 

The extent and relative productiveness of the bottoms, as classified 
in this report, are shown in the table following. 



NATURAL OYSTER BEDS OF DELAWARE. 
Oyster Growth on Southwest Bed. 



21 





Area. 


Oysters per acre. 


Estimated 


Character of oyster growth. 


Under 3 
inches. 


Over 3 
inches. 


Total. 


content of 
oysters. 




Acres. 

11 

8 

31 

56 


Bushels. 
40 

99 
18 
4 


Bushels. 

744 

48 

13 

1 


Bushels. 

784 

147 

31 

5 


Bushels. 

8,624 




1,376 




961 




280 






Total 


106 








11,241 













The area of dense growth is near the southern end of the bed and 
is flanked on the east and west, sides by a very scattering growth, and 
on the north and south by depleted bottom. Most of the oysters are 
over 3 inches long and they appear to be in numerous small patches 
on the soft mud. The place has the appearance of bottom which has 
been overlooked by the oystermen and may as a whole be somewhat 
smaller in area than is indicated in the preceding table. 

The bottom bearing scattering growth lies at the northeast edge of 
the bed and at its southwestern limits merges into a strip of very 
scattering growth running along the western edge of the bed as far 
as the densely covered bottom first described. • ■ There is another 
small patch of very scattering growth near the southeast corner of 
the bed. 

The depleted bottom lies in three patches, one at each end of the 
bed and the other at the middle of the eastern edge. 

Although it is not known whether Southwest bed was dredged 
during the past season, it bears every evidence that it has been over- 
worked. Excepting on the small area of dense growth there are few 
marketable oysters, and bare or almost bare muddy spots are of 
frequent occurrence. Many oysters had been killed by drills and 
many of these animals and their egg cases were found. 

The following table shows the results of examinations: 

Details op Examinations of Southwest Bed. 



Station 
num- 


Date of 
examina- 
tion. 


Depth 
of 

water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


126 


1910. 
June 30 
June 22 
June 30 
...do .. 


Feet. 
14 
13 
13 
12 
15 
14 
13 
14 
12 
13 
15 
15 




No. 
1.5 
5.6 
0.4 
1.5 
0.0 
0.0 
0.0 
0.4 
0.0 
0.0 
0.0 
0.0 


No. 

10.0 
22.7 
5.6 
7.5 
1.4 
4.4 
0.0 
4.4 
1.4 
0.0 
0.0 
0.0 


No. 

74.4 
4.8 
0.4 
0.4 
3.0 
1.5 
0.0 
0.0 
0.4 
0.4 
0.0 
0.0 


Bu. 
40 
99 
21 
31 
5 
15 

17 
5 





Bu. 

744 

48 

4 

4 

30 

15 





4 

4 






Bu. 

784 


31 




147 


121 




25 


122 


...do... 


35 


128 


...do 


do 


35 


129 


...do 

June 22 
June 30 
...do 


....do 


30 


32 







120 


do 


17 


123 


...do... 


9 


124 


...do 


do 


4 


125 


...do 


do 





127 


...do 


.....do.. 














22 



.NATURAL OYSTER BEDS OF DELAWARE. 



STONE BED. 

This bed possibly takes its name from the quantity of hard, sandy 
worm tubes, known to the oystermen as "stone coral," which are found 
attached to and overgrowing the oysters. It is probable that a good 
many of the latter are stifled and killed by this growth, which is 
even more abundant on a small depleted patch lying between the 
Stone bed and the mouth of Mahon River. 

The bed covers an area of about 33 acres of very scattering growth, 
on which there is an average of about 53 bushels of oysters per acre. 
It is estimated that about July 1, 1910, there were on the entire bed 
about 1,750 bushels of oysters, the large and small being in about 
equal quantities. 9 

The following observations were made: 

Details op Examination of Stone Bed. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


36 


1910. 
June 22 
June 29 


Feet. 
13 
18 




No. 

0.7 


No. 
4.8 
10.0 


No. 
2.6 
2.4 


Bu. 
19 
35 


Bu. 

26 
24 


Bu. 
45 


104 




59 











EAST LINE BED. 

This bed lies just at the line which marks the southern limits of the 
public grounds, and it appears that for that reason it has a sentimental 
interest to the oystermen. It has a diameter not much greater than 
the length of a boat and is too small to plot on the chart, on which its 
position is indicated by a circle. 

Numerous examinations were made in its vicinity over an area 
of 6 or 8 acres, but at only one place were oysters found, and there 
they were very dense and mostly of marketable size. 

The data obtained at this station are shown in the following table: 

Details of Examinations of East Line Bed. 



Station 


Date of 
examina- 
tion. 


Depth 

of 
water. 


Character of growth. 


Oysters caught per 
square yard. 


Estimated quantity 
oysters per acre. 


ber. 


Spat. 


Culls. 


Counts. 


Seed. 


Market. 


Total. 


118 


1910. 
June 30 


Feet. 
13 




No. 

0.0 


No. 
10.0 


No. 
77.8 


Bu. 
35 


Bu. 

778 


Bu. 
813 









NATURAL OYSTER BEDS OF DELAWARE. 23 

FLOGGER BED. 

Flogger bed lies along Joe Flogger Shoal, which separates Blake 
Channel from the ship channel. As developed by the survey, it is 
the largest bed in Delaware, having a length of over 3 miles, an average 
width of about one-third mile, and an area of about 660 acres. Owing 
to its exposed situation and the depth of water, as well as to the con- 
tradictory information received as to its approximate location and 
extent, it was the most troublesome bed encountered by the survey. 
Lines were run across Joe Flogger Shoal from its extreme southern 
end, but no indications of shells or oysters were encountered until 
within about one-half mile of east line. From this point scattering 
shells were found, but when the bottom was examined with the tongs 
these were discovered to be more or less submerged in the sand. 

The bed as outlined on the chart was located almost entirely by 
means of the chain. At its upper end it lies on the eastern or ship- 
channel side of Joe Flogger Shoal, but about a mile from its upper 
end it expands to the westward over an area of somewhat deeper 
water, and thence, to its southern end, continues on the western or 
Blake Channel side of the shoal. It was at this point of expansion 
only that oysters were found, in one small patch of very scattering 
growth and two or three areas of depleted bottom. - The results were 
not of sufficient importance to exhibit in detail on the chart. It is 
possible that oysters are to be found in limited quantities in some of 
the deeper water, but the chain readings did not indicate patches of 
sufficient importance to warrant the expense of making dredgings. 
It is reported that there are oysters in some of the deep water of the 
ship channel, but no indications were found in such places as were 
examined. 

It is understood that Flogger bed has not been dredged for several 
years, and the survey indicated that while formerly it may have been 
of importance commensurate with its area, it has become covered with 
sand throughout practically its whole extent. It may again become 
productive, but there is no present indication of this probability. 

Oysters were reported around the buoy at the head of Flogger Shoal 
and at another buoy on the opposite side of Blake Channel, but a care- 
ful examination, expecially in the latter place, failed to disclose them. 

THE BEDS IN SUMMARY. 

The oyster bottoms of Delaware all lie between Woodland Beach 
and the vicinity of Bowers Beach, covering an area about 21 miles 
long and with an average width of about 3 miles. South and west of a 
line running east from the old Mahon River Lighthouse and thence 
approximately southeasterly along Blake Channel, the bottoms are 
excluded from the common oyster fishery and a considerable propor- 
tion of the area is leased to private persons and firms for purposes of 
oyster culture. 



24 



NATURAL OYSTER BEDS OF DELAWARE. 



With this area this report will not deal, as it was examined by the 
writer in but the most cursory manner and the survey of the private 
beds was being made solely as a State undertaking. It may be stated, 
however, that the private beds are planted partly with shells, mostly 
brought from points on Chesapeake Bay, but generally with seed 
oysters taken from the natural beds. The grounds are in large part 
leased or controlled by residents of Philadelphia and New Jersey, and 
the product is consumed principally in Philadelphia, being marketed 
through Maurice River Cove in New Jersey. 

The natural rocks, with which alone this report is concerned, lie in 
a narrow strip between Blake Channel and the main ship channel on 
what is known as Joe Flogger Shoal, and between these channels and 
the Delaware shore in a belt which stretches from the east line above 
mentioned to about abreast of the upper pier at Woodland Beach, a 
distance of about 13 miles. 

At its southeastern end, where it adjoins the planted area, this zone 
is about 3 miles in width, but it gradually narrows to the northward 
until at its upper extremity it is hardly one-half mile wide. The most 
extensive beds lie in the lower half of the zone and the most intense 
fishery is carried on in that region. During the time of the survey 
this was practically the only place in which the dredgers were operat- 
ing, and we were informed that but little had been done elsewhere 
earlier in the season. 

The following tables summarize the data of the extent, condition, 
and general distribution of oyster growth on the several beds pre- 
viously discussed in more detail : 

Areas of Oyster Beds. 





Character of oyster growth. 




Name of bed. 


Dense. 


Scatter- 
ing. 


Very 
scatter- 
ing. 


Depleted. 


Not 
deter- 
mined. 


Total. 




Acres. 
Ill 
6 
109 


Acres. 
12 
14 


Acres. 
6 
55 
15 
21 
11 


Acres. 
26 
3 
39 


A cres. 


Acres. 
155 






78 






163 








21 


Sand 


16 
4 




27 




54 








4 




8 

5 

20 


17 
7 
45 
12 
19 
65 
7 
20 






25 






5 
140 

12 
171 




17 


Silver 


65 
3 
16 
49 




270 


Between Silver and Ridge 


21 


36 




21 

86 


68 


Ridge 




371 


Northeast of Ridge 




7 


Old 




17 





37 


Outside of Old 


16 
11 
11 






16 










12 


23 




8 


31 
33 


56 


106 






33 




(') 








(') 


Flogger 








2 660 


060 














Total 


417 


174 


364 


496 


693 


2,144 







1 Less than 1 acre. 



2 Practically all depleted. 



NATURAL OYSTER BEDS OF DELAWARE. 25 

Estimated Oyster Content of Natural Beds, July 1, 1910. 





Character of oyster growth. 




Name of bed. 


Dense. 


Scatter- 
ing. 


Very 
scatter- 
ing. 


Depleted. 


Not 
deter- 
mined. 


Total. 




Bushels. 

40, 515 

1,164 

29, 975 


Bushels. 
2,512 
1,106 


Bushels. 

162 
1,925 

615 
1,200 

700 


Bushels. 


Bushels. 


Bushels. 
43, L89 








4,195 








30, 590 










1,200 




3,700 
3,000 




200 




4.600 






3,000 




900 

375 

2,180 


750 
375 

2,070 
420 
950 

3,705 
200 
840 






1,650 










750 




15, 925 
2,500 
3,552 
8,907 


1,400 

84 
S55 


13,000 


21,575 




5,920 




1,995 
10, 406 


6,581 


Ridge 


23, 933 




200 


Old 






221 




1,061 


Outside of Old 


6,800 
5, 300 
8,624 




6,800 










i 15,000 


20,300 




1,376 


961 
1,750 


280 


11,241 






1,750 




1500 








■500 










( 2 ) 


( 2 ) 














Total 


130, 522 


20,850 


16, 623 


3,040 


18, 000 


189,035 







■ Estimated from chain indications. 



2 Practically all depleted. 



Combining the foregoing data, an interesting comparison may be 
instituted between the beds sustaining a heavy fishery with dredges 
and those which recently have been worked but little. According 
to the best information, supported by our own observations in the 
latter part of the season, practically all of the dredging in 1910 was 
on the beds south of Over-the-Bar, although a few vessels were 
observed apparently working on Thrum-cap.' These beds, excluding 
Flogger, had a total area of 1,088 acres and a total estimated oyster 
content of 111,061 bushels, or an average of 102 bushels per acre, at 
the end of the season. On the beds which were reported or observed 
to be most severely worked the oyster content averaged considerably 
less than this. On the Ridge the average for the whole bed was about 
60 bushels per acre, on Drum bed about 97 bushels, on Silver bed 
about 80 bushels, on Old bed 30 bushels, and on Southwest bed about 
106 bushels, and for the five beds taken as a whole the average was 
about 75 bushels per acre. 

The beds above and including Over-the Bar have an area of 396 
acres and a total estimated content of 77,984 bushels of oysters of all 
sizes, or an average of 197 bushels per acre. These beds, owing to 
their position, are probably more subject than the lower beds to dam- 
age from freshets and are probably naturally less productive, yet 
they had at the time of examination an oyster growth over 2\ times 
as dense. If we consider the various small patches surrounding the 
five beds enumerated above, which are in general too small to dredge 
or which, if large enough, have been overlooked during the season 



26 NATURAL OYSTER BEDS OF DELAWARE. 

recently closed, the disparity is still greater. Those which were 
examined by tonging had an area of 46 acres and an estimated 
content of i8,000 bushels of oysters, an average of nearly 390 bushels 
per acre, over five times the density of growth on the large beds in 
the vicinity. 

The number of bushels taken from the beds of Delaware during the 
past season is not known but it was probably several hundred thou- 
sand bushels, and from the conditions found in the survey and the 
data just deduced it probably can be safely assumed that oysters 
were from three to five times as abundant at the beginning of the sea- 
son as they were in its closing days when the survey was made. 

This heavy draft on the beds would be less serious were it not 
accompanied by an abuse for which there is no excuse. In a region 
devoted mainly to planting and where a comparatively small quantity 
of oysters is marketed directly from the natural beds it is economically 
advisable to permit the taking of small oysters as well as large. So 
long as there is an abundance of shells on the bottom and a reasonable 
quantity of oysters is left to furnish spawn there will be, under favor- 
able conditions of water and temperature, a more or less regular set 
of spat and the oyster population of the beds will be fairly maintained, 
although, of course, the proportion of oysters of marketable size will 
diminish. When, however, the beds are stripped of shells, as appears 
to be the case in Delaware, they will surely become depleted. 

During the survey, although a number of vessels were actively 
dredging, no member of the party observed a boat engaged in culling. 
Inquiry among the oystermen elicited the information that while the 
boats catching seed oysters for sals generally cull their catch because 
the planters will not pay oyster prices for shells, the vessels owned 
or operated by planters when dredging on the public beds rarely do 
so. They are charged with carrying away everything which the 
dredge. picks up, the shells being valuable for hardening the bottoms 
on their planting grounds and as cultch for catching a .set of spat. 

That some vessels are guilty of such behavior is within the knowl- 
edge of the writer, and moreover the charge is supported by the con- 
dition of the beds. One of the most noteworthy of the facts disclosed 
by the tong examinations was the small quantity of shells found as 
compared with similar examinations of beds in other States. On 
the five important beds in the vicinity of the Ridge there are less 
than 2 per cent as many shells per square yard as are found on the 
seed beds of James River, Va., where culling is strictly enforced. In 
places the deep pavement of shells which must have existed formerly 
has been completely removed and the underlying mud now shows 
itself in patches in the midst of the beds. A hard-worked bed to be 
in a healthy condition should contain an abundance of shells. The 
ultimate result of the continuance of this state of affairs is not difficult 



NATURAL OYSTER BEDS OF DELAWARE. 



27 



to foresee. Oysters can not set on the mud. They must have some 
hard, clean object to which to attach when they settle down from 
their infantile free-swimming habit, and on the beds the old shells 
and the oysters themselves offer the only possibilities. If there be 
few or no shells the recuperation of exhausted beds is correspondingly 
retarded. If both shells and oysters are persistently removed, the 
most productive bed eventually will be hopelessly depleted. 

PHYSICAL AND BIOLOGICAL CONDITIONS. 
TIDES AND CURRENTS. 

A staff tide gauge was established at the wharf at Mahon River 
Light-house and readings were taken hourly from 8 a. m. until 5 p. m. 
during the period of the survey. This does not furnish a very accurate 
plane of reference, but as the location of the gauge was central with 
respect to the more important beds it is sufficiently accurate for the 
purposes of this report. The average rise and fall of the tide between 
June 19 and July 10 was 5.4 feet, the minimum being 4.5 feet on July 
10 and the maximum 6.3 on July 2. 

No measurements of the velocity of currents were made, but in 
general it may be stated that they are strong throughout the region 
embraced in this report. 

SALINITY OF THE WATER. 

The salinity of the water exhibited a very considerable range 
within the limits covered by the survey. From June 18 to July 10 
observations were made three times daily at the anchorage of the 
Fish Hawk and several times each day on the oyster beds undergoing 
examination. Most of the observations on the Fish Hawk were made 
at a point about 1 mile south of the east line and about 3 miles 
offshore, but others, fewer in number, were made near the southern 
limit of the planted beds, near the middle of the north and south 
extent of the public beds, and at the upper limit of oyster growth 
opposite Woodland Beach. 

The data obtained are shown in the following table: 

Salinity of Water Over Oyster Beds, June 18 to July 10. 



Locality. 





Specific gravity of water corrected. 


of obser- 












vations. 


Maximum. 


Minimum. 


Average. 


3 


1.0074 


1.0032 


1.0057 


3 


1.0121 


1.0100 


1.0107 


33 

6 


1.0149 
1.0178 


1.0103 
1.0158 


1.0136 
1.0164 



Average 
tempera- 
ture of 
water. 



Opposite Woodland Beach 

Midway between Ship John and Elbow Light- 
house 

3J miles southeast by east of Mahon River 
Light 

6 miles east-northeast of Bowers Beach 



"F. 



28 NATURAL OYSTER BEDS OF DELAWARE. 

At the upper limit of oyster growth the salinity of the water was 
low at a time when there had been comparatively little rainfall, and 
it is probable that it may become practically fresh at this point during 
periods of freshet. This is without much doubt the cause inhibiting 
the growth of oysters at places higher up the river. 

At the southern end of the planting grounds the salinity is com- 
paratively high and in consequence it is to be expected that the drill 
or borer would be destructive. On the more important of the public 
beds, those lying between the east line and the mouth of Leipsic 
Creek, the density is favorable for the welfare of the oysters. It 
probably never falls so low as seriously to threaten the beds, and, on 
the other hand, it is hardly high enough, excepting close to the east 
line, to favor an abundance of drills. 

ENEMIES OF THE OYSTER. 

It is stated that schools of drumfish occasionally appear on the 
oyster beds of Delaware Bay and cause much damage, but none were 
observed during the survey. This enemy of the oyster is usually 
more destructive on planted beds than on the public rocks, probably 
because the single-culled oysters on the former are easier to crush 
than are the clustered, sharp-edged specimens more common on the 
natural beds. The inroads of the drumfish are sporadic and unex- 
pected in most places, although on the coasts of some of the Southern 
States they are frequent enough to warrant the inclosure of the planted 
beds with wire fences. This appears to be the only really adequate 
protection, though if the presence of a school on the beds or in their 
vicinity is discovered in time it can often be driven from the neigh- 
borhood by the use of explosives. 

The principal enemy to the oyster on the Delaware beds is the drill 
or borer, a small marine snail which drills a hole through the oyster's 
shell and thus gains access to the contents, which it consumes. The 
perforation is made by actual drilling with a rasplike organ protruded 
from the mouth, and so far as is known no acid or other solvent is 
employed to soften the shell. The drill breeds during late spring and 
summer, laying its eggs in vase-shaped, leathery capsules attached 
in clusters to shells and other hard bodies on the bottom. These 
capsules, each containing several eggs, are readily recognizable, 
being about one-fourth inch long and usually yellow in color. 

In the few places examined on the planted beds there were con- 
siderable numbers of drills and many small oysters killed by them. 
On the public beds near the east line some drills and killed oysters 
were found, but over most of the area surveyed the salinity of the 
water is somewhat too low to permit these pests ever to become a 
serious factor. Below a salinity represented approximately by a 
mixture of equal parts of salt and fresh water, having a specific 
gravity of about 1.012 or 1.013, the drill will not thrive. 



NATURAL OYSTER BEDS OF DELAWARE. 29 

Although in the absence of other food the drill will attach and 
sometimes kill oysters of marketable size, it invariably attacks smaller 
ones by preference. Seed oysters 2 or 2| inches in diameter are com- 
paratively immune, and in places where the drills are particularly 
troublesome such seed should be planted in preference to smaller. 
Although such is not known to be the case in Delaware, there are 
localities in which it is useless to plant shells or other cultch, as the 
spat is drilled before its shell has lost its first paperlike thinness. 

The drill is a difficult enemy to combat. Where it is sufficiently 
abundant to be a menace on private beds' the oysters are usually 
dredged up and the drills removed by hand and destroyed, after 
which the oysters are again laid down. Much can be done by destroy- 
ing the drills and their egg capsules wherever found. The common 
practice of some Delaware planters of depositing rough seed on their 
beds undoubtedly helps to maintain the abundance of the drill. 

o 



LBJL12 




Natural Oyster Beth *Unwn in red 

jr>-<r of dense growth of oyste 

" " Mrtitlrrrtl 

depleted 

Aoandif'.'/' 

Depth at m»'ujt low prater expressed, iji /bet. 

Bottom eymboU 

A. tor hard *. for so/i 



US BF -Doc 729 




